If it's not your fault then you are entitled to a full repair of the car or the cost of a car in exactly the same condition as yours before the crash. So if they write it off use any photos you have of it before the crash and sales ads to make sure you get as much cash as possible. They will make you offers that are below the cost of a new one, DON'T accept any less than what it will cost to either get yours back to pre crash condition or a same quality replacement. Keep refusing till they offer you enough.